Printing system using a continuously moving platen

ABSTRACT

There is disclosed a dot matrix or telegraphic progressive printing system including an encoding device such as keyboard or reader, a code translator, and a printer for progressively printing a symbol on a record medium during each printing cycle. In the illustrated embodiments, a platen having platen edges rotates continuously, a carriage travels at a constant rate relative to the platen during each printing cycle, and a print hammer mounted by the carriage cooperates with successive platen edges or elements of the platen in accordance with the symbol pulse units received from the code translator. The printing cycle for a selected symbol is initiated when a stored signal is ready to be applied to the printer and a platen element is in the proper position relative to the print hammer.

United States Patent l 13,629,502

3,324,240 6/1967 Kleinschmidt et al........

Wllburn F. Bradbury l78/25 Northbrook, lll. 3,29l,909 l2/l966 Clark et al. [78/25 [2 l] App! 2 Primary Examiner-Kathleen H. Claffy d Assistant Examiner.lan. S. Black [45] Pateme scn'd carponfion Attorney-Mason, Kolemainen. Rathburn 8L Wyss New York, N.Y.

ABSTRACT: There is disclosed a dot matrix or telegraphic progressive printing system including an encoding device such [72] Inventor [22] Filed [73] Assignee as keyboard or reader, a code translator, and a printer for progressively printing a symbol on a record medium during each printing cycle. In the illustrated embodiments, a platen having platen edges rotates continuously, a carriage travels at 1 a constant rate relative to the platen during each printing cycle, and a print hammer mounted by the carriage cooperates with successive platen edges or elements of the platen in accordance with the symbol pulse units received from the code translator. The printing cycle for a selected symbol is initiated when a stored signal is ready to be applied to the printer and a platen element is in the proper position relative to the print rr mm m aw o mmmnm mm 83 7 8. Y 71%9 7 9 mw U 0 m m N u u 6 N u 0 m m 6 E m C m m ..0/. T m A 4 .nM m m S .Pa n E m w r m m 3 mm m B u u U .m m m "T m m -mm m I w YA T Mn N mm m m un N-I l| -01 0 Nw C a. 1 m w. s o o PMl U .mF M l I ll 1 w m m mm m u PATENTEU M621 um 3529.502

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sum 7 OF 7 PRINTING SYSTEM usmo A CONTINUOUSLY MOVING sures BACKGROUND OF THE INVENTION 1 Field of the Invention This invention relates in general to the art of dot matrix printing systems and in particular to telegraphic progressive printing systems.

2. Description of the Prior Art A printing system disclosing a prior development in the art to which this invention pertains is found in U.S. Pat. No. 3,324,240.

SUMMARY OF THE INVENTION The invention comprises a system for dot matrix printing of successive symbols on a record medium. A symbol signal generated at a keyboard, a reader, or the like is translated into a signal having pulse units representative of the selected symbol. A selected signal is stored, for example when a corresponding symbol key is depressed, and concomitantly a predetermined pattern is set up in a matrix. The printer has a continuously moving platen with platen elements or edges and a print hammer mounted on a carriage which moves relative to the platen. When a signal has been stored and a platen element is in proper position, as sensed by a sensing device, to start progressive printing at one or more locations in a first column on the record medium, operation of a commutator is initiated. Initiation of operation of the commutator is considered to initiate readout of the stored signal and hence to initiate the printing cycle. The commutator operates in synchronism with the speed of the platen elements. The platen continues to move even though the printing cycle for one symbol is complete. In like manner, when the next signal has been stored and the platen is in proper position as sensed by the sensing device, the printing cycle for the next symbol commences.

The invention also comprises improved carriage and carriage-guiding structure and transducer mounting structure. Various other objects and features of the invention will be apparent from the drawings and the description of the preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic view of a dot matrix printing system including a keyboard, a code translator, and a printer having a platen with platen edges and a cooperating print hammer;

FIG. 2 is a cutaway perspective view of the principal components of the keyboard and code translator depicted in FIG. 1;

FIG. 3 is a vertical sectional view of a commutator, its drive train, and a start-stop mechanism depicted in FIG. 2;

FIG. 4 represents the commutator segments wired for the letter E;

FIG. 5 is a schematic layout of the 48 segments of the commutator, a portion of an exemplary diode matrix group, and several of the key switches; the matrix group portion shown is wired to the proper commutator segments and to selected key switches to result in transmission of the letters M, H, B, E, S, V, and X when the respective key switch is closed;

FIG. 6 is a perspective view of a tape reader;

FIG. 7 is a side elevational view of a printer for carrying out the invention;

FIG. 8 is a fragmentary perspective view of the side of the printer depicted in FIG. 7;

FIG. 9 is a fragmentary side elevational view showing various components in different positions from the position shown in FIGS. 7 and 8;

FIG. 10 is a front elevational view of the printer;

FIG. 11 is an enlarged fragmentary elevational view showing the side of the printer which is opposite from the side shown in FIG. 7;

FIG. 12 is a fragmentary view as viewed upwardly and rearwardly from the lower front part of the printer;

FIG. 13 is a fragmentary sectional view of a clutch, a drive pulley and a gear shown in elevation in FIG. 10;

FIG. 14 is an enlarged sectional view showing the platen in relation to a carriage which carries a print hammer, the print hammer being shown out of printing cooperation with the platen and the record medium;

FIG. 15 is an elevational view of the carriage, the print hammer, and fragmentary portions of the feed screw and a guiding and actuating shaft or rod, as viewed from the front of the printer;

FIG. 16 is a perspective view of the print hammer;

FIG. 17 is a sectional view through the feed screw and a bearing which is secured to the carriage, together with a frag mentary portion of the feed pawl;

FIG. I8 is a view taken along line l8 18 of FIG. I7;

FIG. 19 is a sectional view taken along line 19-19 of FIG. 17;

FIG. 20 is a diagrammatic view showing another embodiment of the system shown in FIG. I;

FIG. 21 is a diagram of a grid block arrangement showing shaded locations or dots printed during progressive printing of the symbol E;

FIG. 22 is a diagrammatic view showing in detail structure depicted by logic symbols in FIG. 20;

FIG. 23 is a fragmentary view showing the arrangement by which a symbol, such as symbol E, can be stored in the code translator;

FIG. 24 is a diagrammatic view showing how the pulse units of a symbol signal can be sensed during readout in a predetermined sequence;

FIG. 25 is a front elevational view of a drive motor, position-sensing devices, and structure for mounting the sensing devices to a shaft which is driven by the motor;

FIG. 26 is an elevational view of the motor, sensing devices, and mounting structure as viewed from the left side of FIG. 25;

FIG. 27 is a fragmentary top plan view taken along line 27- 27 of FIG. 25;

FIG. 28 is a circuit diagram illustrating a variable rate time base generator or oscillator illustrated in logic symbol form in FIG. 20;

FIG. 29 is a circuit diagram of a one-shot m'ultivibrator illustrated in logic symbol form in FIG. 20;

FIG. 30 is a circuit diagram of a print hammer operating circuit and amplifier illustrated in logic symbol form in FIG. 20;

FIG. 31 is a circuit diagram illustrating a transducer circuit shown in logic symbol form in FIG. 20;

FIG. 32 is a circuit diagram of a one-shot multivibrator shown in logic symbol form in FIG. 20;

FIG. 33 is a circuit diagram illustrating a sense amplifier shown in logic symbol form in FIG 20;

FIG. 34 is a circuit diagram of an integrated circuit l/IO decoder-and associated NAND gates shown in logic symbol form in FIG. 20; and

FIG. 35 is a fragmentary view of a keyboard for storing signals in a memory device depicted in FIG. 20, a control register, a sense amplifier, and an arrangement for effecting carriage return.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The keyboard 36 has symbol-selecting means in the form of a-set of keys 38, only one of which is illustrated. When the selected key 38 is depressed it will pivot associated levers 41 and 42 counterclockwise (FIG. 1) to in turn pivot associated switch operator lever 47 clockwise. Clockwise pivoting of lever 47 will close associated leaf switch 49 and will thereafter effect closing of a leaf switch 50.

Closure of the switch 49 completes a circuit to a diode matrix or diode matrix bank 51, thereby setting up a predetermined circuit through certain diodes in accordance with the key 38 which was depressed. It is apparent that depression of any key 38 effects storage of its respective symbol signal. Closure of the switch 50 completes a circuit to the starting mechanism for a commutator 52, provided a switch 50' of the printer 37 is closed. Thus, when both switches 50 and 50' are simultaneously closed, a circuit is completed through a oneshot multivibrator 55 to a starting electromagnet 56. Energization of the electromagnet 56 causes attraction of an armature 57, best shown in FIG. 2, pivoting it until its blocking end 58 moves out of the path of a blocking lever 59. With the blocking end 58 removed from its path, blocking lever 59 and commutator shaft 60 will start rotating due to force trans mitted from a motor 64 through gears 63 and 62 and a slip clutch 61.

A wiper disk 66 (FIG. 3) attached to the commutator shaft 60 works in sliding contact relationship with a brush contact 67. A wiper 65 carried by the disk 66 can make wiping contact with the segments of the commutator 52. It is through the brush contact 67 that electrical pulse units are sent over an output line to an amplifier 68. The code translator 39 and the amplifier 68 can be located either at the transmitting station or at the receiving station. The code translator 39 is considered to include the matrix 51 and the commutator 52.

The portion of the matrix 51 shown in FIG. of this application differs from the one shown in FIG. 23 of U.S. Pat. No. 3,324,240, in that (in FIG. 5) segments designated No. 39, No. 40, and No. 41 are dead segments because they are not part of any circuit, segments No. 42 and No. 43 are electrically connected to the output of an oscillator 70 which generates a continuous signal at a particular frequency, for example, 1,500 cycles per second, and segments No. 36, No. 37, and No. 38 are electrically connected to the output of a gated oscillator 71 which generates signals at a selected frequency which is different from, and in particular is higher than, the frequency of the signals generated by the oscillator 70. For example, the oscillator 71 is one that generates a continuous signal of 2,000 cycles per second.

So long as the electromagnet 56 remains deenergized, the wiper 65 will remain in contact with the dead segment No. 40. When the selected key 38 is depressed it will cause closure of the switch 49 thereby setting up the circuit paths for the selected symbol, and thereafter when switches 50 and 50 are closed to energize the electromagnet 56, the blocking end 58 moves out of the path of the blocking lever 59 enabling the shaft 60, the wiper 65, and the disk 66 to make one complete revolution at constant rotational speed. As the platen 127 is in proper position when electromagnet 158 is energized, initiation of the printing cycle of the printer 37 is synchronized with the code translator 39. During this complete revolution, the wiper 65 will successively make wiping contact with segments No.41, No. 42, No. 43 and segments No. 1 through No.7, No. 8,, No. 8 through No. 14, No. through No. 21, No. 22,, No. 22 through No. 28, No. 29,, No. 29 through No. 35, No. 36,, and No. 36 to No. 40. When the wiper 65 makes contact with the dead segment No. 41 no signal is generated; however, when the wiper 65 makes contact with abutting segments No. 42 and No. 43 the output signal from the oscillator 70 will be applied to the amplifier 68. This signal will be detected by a detector 70 which is connected to the amplifier 68. The detector 70' detects any signal having a frequency of 1,500 cycles per second or higher; detection of this signal will effect energization of a clutch coil 232. Each energization of coil 232 will cause starting of a start-stop device, specifically it will cause engagement of a clutch 203 (FIG. 10), to cause a printer carriage 164 to move away from the start-of-line position. As the wiper 65 successively makes wiping contact with segments No. l through'No. 35, an electrical symbol signal composed of a succession of selectively time-spaced electrical intrasignal pulse units representative of the selected symbol will be applied to the amplifier 68. For example, for the symbol or letter B segments No. 1 through No. 8, No. 11,'No. 14, No. 15, No. 18, No. 21, No. 22, No. 25, No. 28, No. 29, and No. 35 (FIGS. 4 and 5) are connected via circuit paths of the diode matrix 51 to positive potential through the switch designated E in FIG. 5; therefore, as the wiper 65 successively makes contact with each of these segments an electrical pulse unit, in particular a current pulse unit, will be applied to the amplifier 68. It is apparent that the time-spaced pulses generated as the wiper 65 wipes across the segments No. 1 through No. 35 will be of the binary type, in this instance either of the current type or of the no-current type. Current pulses are detected by a print pulse detector 72 which is connected tothe amplifier 68. A print coil 316 is energized each time a current pulse is detected by the print pulse detector 72. When the wiper 65 completes its contact with the segment No. 35, the symbol will be completely printed. As the wiper 65 wipes across abutting segments No. 36, No. 37, and No. 38, the signal generated by the oscillator 71 will not be applied to the amplifier 68 unless the carriage return key 38' is depressed. It is only when the carriage-return key 38' is depressed and the wiper 65 wipes across segments No. 36, No. 37, and No. 38 that the oscillator 71 is gated and thus applies a 2,000 cycle per second output signal to these segments. A detector 71' will detect the signal generated by the oscillator 71, as amplified by the amplifier 68, to cause energization of a carriage return coil 259. As the frequency of the signal which is applied to detector 71' is also applied to the detector 70', and as that signal is of a higher frequency, namely higher than 1,500 cycles per second, the detector 70' will also detect that signal, thereby also energizing clutch coil 232. Depression of the carriage-return key 38' will not set up any current paths in the matrix 51 as its associated switch 49 is not connected to the matrix 51.

The transmitter which is used can include a keyboard as depicted in FIGS. 1 and 2, a tape reader R as depicted in FIG. 6, or the like. When using a reader instead of a keyboard in the embodiment of FIGS. 1 through 5 and 7 through 19 the reader would be of a type having one output corresponding to each symbol which is to generate; in particular, each output would be connected to the diode matrix 51.

The printer 37 is shown in detail in FIGS. 7 through 19 of the drawings. Some of the printer components depicted in this application are similar in construction to the printer components disclosed in US Pat. application Ser. No. 632,955, to which reference may be had for additional details. The printer 37 is shown to include a continuously driven platen 127 having a plurality of equally spaced parallel platen elements or edges 138 about its periphery. The platen elements 138 extend the full length of the platen 127. A record medium R (FIG. 14) is disposed between the platen 127 and a lineshaped print face 142 of a print hammer 299. The record medium R is preferably composed of treated paper so as the print face 142 impacts the paper and presses the paper against the cooperating platen edge 138, a permanent contrasting mark is formed thereon. In the event it is desired to use untreated paper, an ink ribbon (not shown) can be fed between the print face 142 of the print hammer 299 and the untreated paper.

An electric motor 199 (FIG. 1) drives the platen 127 at constant speed through toothed pulleys 200 and 202 and a toothed belt 201, and gears 307 and 308. Secured to platen drum shaft 302 is a cam 303 which has equally spaced-apart cam lobes 304 equal in number and corresponding to the platen elements 138 of the platen 127. As the cam 303 rotates, lobes 304 acting on switch arm 305 of the switch 50' cause the contacts of the switch 50 to open and close. The position of the switch 50' is adjustable with respect to the cam 303 by an adjusting screw 306. When the switch 50' is properly adjusted, printing of a symbol on the record medium R will be initiated when the element 138 is in the proper position with respect to the face 142 of the print hammer 299.

Referring to FIGS. 7 through 19, a frame 121 is shown to rotatably mount the platen drive shaft 302, a feed screw 193, a shaft 163, and a guiding and actuating member or shaft 165 which is parallel to the feed screw 193. The feed screw 193 is driven whenever the clutch 203 is engaged. When the electromagnet 229 (FIG. 11) is energized, the latch element 228' is tripped to enable am 240 to pivot counterclockwise out of abutment with tooth 241. Thereupon, wrapped spring 213 (FIG. 13) engages clutch surface 217'. Engagement of the clutch 203 causes the feed screw 193 to make one complete revolution, thereby driving carriage 164 a distance equal to one symbol space plus a small additional distance to provide a space between each symbol and the next successive symbol. The carriage 164 is mounted for travel lengthwise with respect to the platen 127.

Carriage return is accomplished by energizing electromagnets 229 and 158, thereby engagingthe clutch 203 to cause rotation of the feed screw 193 and tripping latch member 255' to enable lever 250 to pivot clockwise (FIG. 9). The lever 250 has a pin 272 against which a latch member 270 is urged by a spring 273. The latch member 270 has a hub 27] which is secured to the shaft 165. As the lever 250 pivots clockwise (FIG. 9), the pin 272 drives member 270 and shaft 165 clockwise. When the shaft 165 pivots clockwise (FIGS. 9 and 14), a spring 196 pivots a coupling member in the form of a feed pawl generally indicated at 190 out of coupling engagement with the feed screw 193 and a bearing 308 which is secured to the carriage 164. A carriage-return spring 277 (FIG. connected at one end to a bracket 277 secured to the carriage 164 is trained about a pulley 309 and is connected at its other end to the frame 121. When the lever 250 is pivoted clockwise (FIG. 9), a roller follower 261 carried by the lever 250 moves into the path of the cam 207. As the cam 207 is rotated one revolution, feed pawl 262 drives ratchet wheel 263 which in turn drives the shaft 163. Gears I62 and 162' secured to the shaft 163 mesh with and drive gears 160 and 161, thereby driving feed wheels 146 and 147 which cooperate with rollers I54 and 155 to feed the record medium R. When adjustable screw-type actuator 281 mounted by the carriage 164 strikes a latch member 274 (FIG. 8), a latch 270' formed by latch members 270 and 274 is tripped to enable latch member 270 to pivot counterclockwise (FIG. 9) under the force of the spring 273. A resilient stop or bumper 282' (FIG. 15) secured to a carriage frame 309 strikes the side panel of the frame 121 and defines the start-of-line position of the carriage 164.

The carriage frame 309 has mounting portions 310 and 311 arranged to provide a U-shaped opening 312. A setscrew 184' is threadably received and mounted by the mounting portion 310. The force which spring 184 exerts on the print hammer 299 can be regulated by adjusting the setscrew 184'. An electromagnet generally indicated at 313 is shown to include a U- shaped core 314 having a leg 315 about which a print coil 316 is received and another leg 317 which is clamped between arms 318 and 319 of the mounting portion 311. Screws 320 pass thorough bores in the arm 318 and through enlarged bores in the leg 317 of the core 314. The screws 320 are threadably received by the arm 319. Hence, the electromagnet 313 is able to be adjusted with respect to armature 321 of the print hammer 299.

A hub 332 is provided at one end of the armature 321 of the print hammer 299. A pivot pin 333, secured in arms 318 and 319, is received in bore 332' of the hub 332. A relatively thin print hammer section 334 is formed integrally with the other end of the armature 321. The armature 321, which is relatively thin, extends in one plane and the print hammer section 334 extends in a plane which is perpendicular to the plane of the armature 321. The pring hammer section 334 joins the armature 321 at an obtuse angle as best seen in FIGS. 14 and 16. The print hammer section 334 has a keeper 335 which receives the marginal end of the spring 184. One end of the spring 184 abuts the print hammer section 334 at lands 336 at each side of the keeper 335. As best shown in FIG. 14, the sprin'g'184 exerts a force on the print hammer 299 at right angles, as is evident from the fact that the centerline of the bore 332' and the lands 336 lie along one straight line and the spring 184 exerts a force against the section 334 along a line that is perpendicular to that line. As the movement of the print face 142 is very small, this relationship remains essentially constant.

The feed pawl 190 is pivotally mounted by a pin 337. A spring 196, the force of which is adjusted by a setscrew196', bears against an extension 340 of the pawl 190. A setscrew 198 is adapted to provide a stop to limit the pivotal movement of the pawl 190 away from the coupled position. As described above, when the electromagnet 158 is energized to enable lever 250 to be urged clockwise (FIG. 9) by the force of spring 253, the shaft also rotates clockwise. With reference to FIG. 14, when the shaft 165 rotates clockwise, a roller 342 rotatably mounted by a shaft 343 secured to the extension 340 loses contact with elongated land 344 of the shaft 165, thereby enabling the spring 196 to urge the pawl counterclockwise to effect uncoupling of the carriage 164 from the feed screw I93 and return of the carriage 164 to the start-ofline position under the force of the carriage return spring 277. Both driving and guiding of the carriage 164 takes place at the bearing 308. The driving force is imparted directly to the bearing 308 by the pawl 190. As driving and guiding of the carriage 164 occur at the same place no twisting moment is imparted to the carriage 164. Yet, driving force is either applied to or removed from the carriage 164 by pivoting the shaft 165 into either one of two positions. A roller 342' is rotatably secured to the carriage frame 309 by a pivot screw 342". The roller 342' makes rolling contact with the shaft 165. Even though the shaft 165 is pivoted to move pawl 190 between coupled and uncoupled positions, there is no tendency to pivot the carriage 164 about the feed screw 193 because the outer surface of the shaft 165 is circular and the shaft 165 rotates about its own axis. During travel of the carriage 164 away from the start-of-line position the force which the land 344 of the shaft 165 exerts on the roller 342 exerts a force on the pawl 190 driving the pawl 190 into meshing engagement with the feed screw 193. This serves to keep the carriage 164 from rocking when the print hammer 299 moves into and out of printing cooperation with platen elements 138. During carriage return, the feed screw 308 and the shaft 165 are the sole guides for the carriage 164.

The feed screw 193 is driven one revolution each time the clutch 203 is engaged. The clutch 203 is engaged each time latch 227 (FIG. 11) is tripped upon energization of coil 232 of electromagnet 229. Tripping of the latch 227 enables unitary lever 234 to be pivoted counterclockwise (FIG. 11) by the force of spring 236, enabling stop arm 240 to pivot out of abutment with tooth 241. When the clutch element 214 rotates, the tooth 241 and cam 239 on its outer surface rotate with it. Arm 238 rides on the outer surface of the element 214. When the cam 239 drives the entire lever 234 clockwise the latch 227 is relatched and the element 114 stops rotating when the tooth 241 again engages the arm 240.

The printer 37 shown in FIGS. 1 and 7 through 19 is also useful in the embodiment of FIGS. 20 and 22 through 34 and in the embodiment of FIG. 35. In FIG. 20, there is shown the platen 127 with its plurality of platen elements or edges 138 mechanically coupled as indicated at 400 to a clock wheel 401. Sensing members in the form of transducers 402 and 403 are in electromagnetic sensing cooperation with two sets of clock elements formed by four slots 402' and 40 slots 403', respectively. There are four locations where the slots 402 and the slots 403' coincide, as best shown in FIGS. 20 and 26. By way of example not limitation, the mechanical coupling 400, which includes the pulley 200, the belt 201, the pulley 202, and gears 307 and 308, provides a drive ratio that causes the clock wheel 401 to rotate six times faster than the platen 127; the platen 127 has 24 platen elements 138, and thus each one of the slots 402' corresponds to one of the platen elements 138.

Referring not more specifically to FIGS. 20 and 22 of the drawings, therein is illustrated a data transmitting system which embodies the present invention and in which the code converter or translating facilities are located at a receiving station. The system includes a transmitter 404 disposed at a location geographically remote from a receiving station and coupled thereto over a channel indicated generally as 404'. The transmitter 404 supplies message information over the channel 404' using any suitable code, but in the illustrative example uses a five-bit or unit.Baudot code in which mark and space conditions are represented by signals of different frequencies. The receiver includes a suitable coupling or interface unit 405 and an amplifier 406 for supplying the received signals to a tone detector 407, the output of which is supplied through an amplifier 408 to a filter capacitor 409 to provide a generally steady state potential representing mark or space conditions. In the illustrated circuit, a more positive or high signal represents a mark signal, and a more negative or low signal represents a space condition.

The incoming signals received from the transmitter 404 and provided at the output of the amplifier 408 are stored in the receiver in their Baudot coded form and are then translated to select a particular write conductor selectively threaded through the cores of a core storage and translating matrix to cause the storage of each received character in the core matrix in the coded form used by the printer. Following the storage of the received character in the core storage matrix, the stored character is read out of the matrix bit by bit to control the operation of the printer.

More specifically, the voltage level signals provided at the output of the amplifier 408 are forwarded through a pair of inverting amplifiers provided by single input NAND-gates 410 and 413 to one input of a NAND-gate 415 over a conductor 416 (FIGS. 20 and 22). The other three inputs to the gate 415 are connected to the or inverted outputs of three flip-flops A, B, and C forming an input counter 500 (FIG. 22). ln the normal state of the receiver, the inverted outputs A, B, and C (shown in the drawings as A, for example) are at the high level potential, and the output of the gate 413 is also at a high level so that the output of the gate 415 is at a low level. The output of the gate 415 is forwarded through an inverting amplifier 417 to apply a more positive potential to the emitter of a transistor in a time base generator or free-running multivibrator 418 (FIGS. 22 and 28) so as to maintain the generator 418 in an inoperative state. The time base generator 418 operates at the bit or unit rate of the received Baudot code.

When the space signal at the beginning of a received character, for example the character E is received, the conductor 416 drops to a low level, the output of gate 415 rises to a higher level, and the gate 417 provides a return for the emitter of the input transistor in the time base generator 418. Thus, the free-running multivibrator 418 is placed in operation. One output of the time base generator 418 is coupled to the clock input of the input flip-flop or stage A in the counting circuit 500 sothat the counting circuit 500 is advanced by the time-based generator 418 in synchronism with the bits of the received character code. The counting circuit 500 controls the selective reading of the bits of the received code into five flip-flops 502, the inputs of which are coupled to the outputs of the inverters 410 and 413 over two conductors 412 and 414, respectively.

Accordingly, when the first output pulse is delivered by the generator 418, the flip-flop A is set to provide a more positive output signal A, while the flip-flops B and C provide the high inverted output signals B and C'. None of the flip-flops 502 are enabled at this time inasmuch as the first bit received from the signaling channel 404 is a space signal forming a start bit. When the generator 418 delivers a second pulse to the counting circuit 500, the flip-flop A is reset, the flip-flop B is set. and the flip-flop C remains reset so that the output signal B and the inverted output signal C are at a more positive potential. This completes the enabling of a gate 504 to supply a negative-going clock or toggle signal to the flip-flop 502 in which is stored the first intelligence bit of the received character. Assuming that the received character is an E, the bit received from the channel 404' is a mark signal so that the output of the inverter 413 is more positive, and the output of the inverter 410 is at a low potential. These potentials are forwarded over the two conductors 412 and 414 to two inputs of the unit 502 so that the first storage flip-flop 502 is set when clocked by the gate 504, and the first flip-flop 502 provides a high signal l and a low-level inverted signal l During the receipt of the next four operating or clock signals from the time base generator 418, the counting circuit 500 is operated through four additional steps to provide in sequence the four output signal or voltage patterns: A, B, C; AZE, C; A, B, C; and A, B, C. In these four settings, the next four flip-flops 502 are enabled in sequence by the pattern of output potentials provided by the counting circuit 500 either directly or through gates similar to the gate 504, as shown in FIG. 22 of the drawings. Since the Baudot code for the character E includes spaces in the second through fifth intelligence bits, none of the remaining flip-flops 502 is set. Thus, at the end of the receipt of these five intelligence bits in the received Baudot-coded character E, the first flip-flop 502 is set, and the remaining four flip-flops 502 are in a reset condition.

The next received bit from the signaling channel 404' is a mark bit representing the stop unit of the code. During the receipt of this code, the seventh operating pulse provided by the time base generator 418 advances the counting circuit 500 to a setting in which all of the inverted outputs of the flip-flops A, B, and C are at a high level. Return of the counter 500 to this setting is used to terminate operation of the time base generator 418. More specifically, the time base generator 418 was placed in operation by the low-level signal applied by the conductor 416 to one input of the gate 415 when the space bit forming the start code was received. When the generator 418 advances the counter 500 to its first setting, the flip-flop A is set so that the inverted output signal A from this flip-flop applied to one input of the gate 415 dropped to a low level and thus maintained through the inverter 417 the enabling for the generator 418. At least one of the flip-flops A, B, and C in the counting circuit 500 was maintained in a set condition during subsequent settings of the counter 500 until the seventh pulse is received. At that time and as set forth above, all of the flip-flops A -C' are reset, and all of the inverted inputs A-C' to the gate 415 are returned to a high level. The conductor 416 is also at a high level at this time because of the received mark bit forming the stop code, and the output of the gate 415 drops to a low level and is forwarded through the inverter 417 to inhibit further operation of the time base generator 418. Thus, the generator is placed in operation on the receipt of the start code and is rendered effective or inhibited on the receipt of the stop code. Thus, the receiver now has stored the received character E in Baudot code in the five flip-flops S02 associated with the input counter 500. The receiver, however, requires one additional item of information before an accurate translation of the stored character into the printer code can take place. More specifically, it is necessary to store an indication of the lowercase or letter shift on the one hand or an upper case or figure shift on the other hand in order to adequately translate the received code stored in the flip-flops 502. This function is performed by a flip-flop 434 (FIG. 20), the inputs of which are provided with the signal 3' or the inverted signal 3" from the third flip-flop 502. The clock input of the flip-flop 434 is connected to the output of a gate 431, the inputs of which are connected to and enabled by the setting of the first, second, fourth and fifth flip-flops 502. These four bits are common to both figure shift and letter shift, and these two combinations differ from each other only in the presence or absence of a mark bit in the third position of the Baudot code. Thus, when a complete character code has been stored in the flip-flops 502 representing either a letter shift or a figure shift, the gate 431 is fully enabled during the receipt of a fifth intelligence bit by a flip-flop 423 in the manner set forth in detail below to' provide a negative-going clock signal to the input of a flip-flop 434. if a figure shift has been received, the inverted input signal 3" is high and theflip-flop 434 is reset. Alternatively, if aletter shift has been received, the input signal "3" to the fiip-flop'434 is high, and this flip-flop is set. Thus, the set condition of the flip-flop 434 indicates reception in lowercase, and the reset condition of the flip-flop 434 indicates reception in uppercase. The output signals derived from the flip-flop 434 are represented by the character 0.

As indicated above, the character stored in Baudot form in the flip-flops 502 is decoded and stored in a core matrix 437 in the positional code used to control the printer. The core matrix includes 35 cores C1-C35 arranged in five vertically extending columns each containing seven cores corresponding to the 35 active positional code bits used by the printer. The Baudot coded character stored in the five flip-flops 502 is translated to and stored in the core matrix 437, in the bits of the positional code required by the printer, by providing a separate write conductor selectively linking those of the cores in the matrix 437 required by the positional code for the character and by energizing the particular write conductor in accordance with a translation of the code bits stored in the flip-flops 502.

As an example, FIG. 23 of the drawings illustrates a write conductor 438 which links nineteen of the 35 cores in the matrix 437 correspondingto the bits of the positional code of the character E. When the conductor 438 is energized, the linked cores or the cores through which the conductor 438 is threaded are set to store the character E in the matrix 437 in the form of the required bits of the positional code used by the printer. These write conductors such as the write conductor 438 are selectively energized by translating the character stored in the flip-flops 502.

More specifically, the output signals 1. 2," and 3" from the three flip-flops 502 are supplied to a translating network 435 of conventional construction which translates the three input signals into a single output marking condition applied to the gate electrode of one of eight silicon controlled rectifiers, one of which is identified as SCR-ZH. The cathodes of these SCRs are connected in common and over a conductor 442 to the output of a monostable pulse generator 440. The anodes of the silicon controlled rectifiers are connected to eight diode networks 435-1 to 435-8. One end of each of the write conductors is connected to one of the diodes in the diode networks 435-1 to 435-8. I

The other end of each of the write conductors is connected to the cathode of one of eight silicon-controlled rectifiers such as a silicon controlled rectifier SCR6V. The anodes of these rectifiers are connected to a source of positive potential, and the gate electrodes of these rectifiers are connected to the output of a conventional translating network 436. The translating network 436 is supplied with the output signals 4 and 5" from the last two storage flip-flops 502, and the output signal 0" from the flip-flop 434. The network 436 translates the three input signals into one of eight output marking conditions applied to the gates of the rectifiers such as the rectifier SCR-6V. As illustrated in FIG. 23, the write conductor 438 for the character E is terminated at one end by connection to the cathode of the rectifier SCR-6V, and at the other end by connection through one of the diodes in the network 435-2 to the anode of the rectifier SCR-ZH. With a Baudot-coded E stored in the flip-flops 502 and the flip-flop 434 set for letter shift, a marking or enabling signal is applied to the gate electrodes of the two rectifiers SCR-6V and SCR-2H to condition the conductor 438 for energization.

The character stored in the flip-flops 502 is translated and stored in the matrix 437 after the fifth bit of the received Baudot code has been received and when one of the elements 138 on the platen 127 is in a proper position to begin recording. More specifically, when the fifth-received intelligence bit of the code is stored in the fifth flip-flop 502 under the control of 1 the signals B and C', a gate 419 (FIGS. 20 and 22) is partially 1 enabled by these same signals, and the enabling is completed by a more positive signal received from the time base generator418 from the collector of the input transistor (FIG. 28). When the gate 419 is fully enabled, a more negative potential is applied to a reset terminal of the flip-flop 423 over a conductor 424 so that the "0" terminal of this flip-flop rises to a more positive potential. This more positive potential is applied to the set input of the flip-flop 423 and is also forwarded through the diode 431' to enable the extended input to the gate 431'. This low input is also applied over a conductor 426 (F 1G. 20') to one input of a gate 425 to drive the output of this gate to a more positive potential which is forwarded over a conductor 430 to the clock or toggle input of the gate 423. The output of the gate 425 is maintained at this high potential by an inverter 429, the output of which is coupled to one input of the gate 425, the output of which is coupled to one input of the gate 425, and the input of which is coupled to the output of a photocell amplifier 402". The input to the amplifier 402" is coupled to the transducer or sensor 402 so that the amplifier 402" normally provides a more positive output or high-level output except when one of the slots 402' on the clock wheel 401 is in reading or sensing position.

At the end of the pulse supplied by the time base generator 418, the gate 419 is no longer fully enabled, and its output rises to a more positive-potential to partially enable the gate 425 and to remove the resetting clamp from the flip-flop 423'. When one" of the vanes 138 01 the platen 127 next moves to a proper synchronized position for initiating a recording operation, the transducer 402 senses the presence of the slot 402' and the amplifier 402" is effective through the inverter 429 to complete the enabling of the gate 425. Thus, a negative-going pulse is applied to the clock terminal of the flip-flop 423, and this flip-flop is set so that its set output provides a more positive potential and a low-level potential is derived from the reset output. This setting of the flip-flop 423 initiates the transfer of the character from the flip-flops 502 to the magnetic core matrix 437.

More specifically, when the flip-flops 423 was in its reset condition, the more positive potential derived from its reset output forwarded over a conductor 423" to the input of a gate 423' initiated the charging of a capacitor (FIG. 29) if a conductor 441 connected to a resistive input of the gate 423' is returned to a more negative or ground potential. When the flip-flop 423 is set and a more negative potential is derived from the reset terminal of the flip-flop 423, the gate 423' triggers the monostable circuit 440 (FIG. 29) so that an output transistor is placed in a conductive condition to return an output conductor 440' to near ground potential. This enables the circuit including the silicon-controlled rectifiers SCR-6V and SCR-2H so that the conductor 438 is energized to set the cores linked thereby, thus causing the storage of the character E in the magnetic core matrix 437 in the bits of the positional code. Further, when the output conductor 440' is returned to a more negative potential the winding 232 is energized to release the one revolution clutch 203 so that the carriage, and the permit hammer 299 which it carries, are advanced through one symbol space. After the delay interval of the monostable circuit 440, the output conductor 440 is returned to a more positive potential to terminate the energization of the winding 232 and the write conductor 438. Thus, the received character E has now been stored in the matrix 437 and the one revolution clutch 203 has been released to initiate the printing operation.

In certain instances, generally those when a control code is received from the line, it is desirable not to store the received control code in the matrix 437 or to initiate movement of the carriage 164 containing the print hammer 299. This function is performed by the gate 431 and a pair of additional gates 432 and 439. As an example, a case shift code is not to be stored in the matrix 437, and thus whenever the gate 431 is fully enabled, a more negative signal is applied to one input of the gate 439 which drives the output of this gate or the conductor 441 to a more positive potential. This prevents charging of the capacitor in the input to the monostable 440 and prevents the setting of the monostable circuit 440. Similarly, when a blank or line feed code is received, the gate 432 will be fully enabled to forward a more negative signal to one input of the gate 439, and similarly inhibit the setting of the monostable circuit 440 through the gate 423.

One additional control function is effected during reception of Baudot coded signals from the channel 404'. A gate 433 is fully enabled by the inverted signals l"-" representing a carriage return. When the gate 433 is fully enabled, the more negative output from this gate is forwarded through an inverter 460 to enable a gate electrode of a silicon-controlled rectifier 461. When the monostable circuit 440 is subsequently enabled, the silicon-controlled rectifier 461 is placed in a conductive condition to energize the winding 259. Energization of the winding 259 is effective as described above to control the printer to perform a carriage return operation. A manual switch 460' is provided for manually controlling the energization of the windings 259 and 232 to effect carriage return and carriage clutching operation.

With the received code now stored in the bits of the positional code in the matrix 437 under the control of the vane synchronizing slots 402' in the clock wheel 401, the readout and sequence of the bits from the matrix 437 takes place under the control of the slots 403' in the clock wheel 401. The slots 403 are sensed by the transducer 403 which is coupled through an amplifier 403" to the input of a counting circuit indicated generally as 444. The counting circuit 444 includes two counters for controlling the application of two coordinate, coincident read currents to the cores of the matrix 437 to control the sequential application of output signals from a common sense winding 447 linking all of the cores C1-C35 to the input of a sense amplifier 448 (FIG. 24).

To control the application of concurrent read currents to the cores C1-C35, the matrix 437 includes five vertical or column read conductors such as two conductors IV and 2V, and seven horizontal or row read conductors such as the conductors 1H and 2. One side of each of the two sets of horizontal and vertical read conductor is returned through an isolating resistor to the collector of a normally nonconductive transistor 435. The other terminations of the vertical or column conductors 1V, 2V is adapted to be connected to ground or a point of reference potential through five siliconcontrolled rectifiers such as the rectifier 445-1, the gate electrodes of which are coupled to a conventional translating network 445. The other terminations of the horizontal or row conductors 1H, 2H are adapted to be connected to a point of reference potential such as ground through seven silicon-controlled rectifiers such as a rectifier 446-1. The control electrodes of the silicon-controlled rectifiers such as the rectifier 446-1 are connected to a conventional decoding or translating network 446. By selectively enabling one rectifier in each of the two groups thereof terminating the horizontal and read conductors, coincident currents can be applied to the cores of the matrix 437 using two coordinate selection to effect sequential readout of the stored information on the sense conductor 447.

The two translating networks 445 and 446 are selectively controlled by the counting circuit 444, and this circuit (FIG. 22) is advanced by transducer 403 under the control of the bit slots 403'. The counter 444 includes a row counter 506 advanced by the transducer 403 and coupled to the decoding network 464, and a column or vertical counter 508 advanced step by step under the control of the network 446 and coupled to the translating or decoding network 445 for selecting the vertical write conductors 1V, 2V.

As set forth above, the flip-flop 423 (FIG. 22) is reset during the fifth bit of the received character and is set on the first signal received from the transducer 402 indicating the recording element 138 of the platen 127 is in proper recording position. The set output of the flip-flop 423 is coupled to the reset output terminals of three flip-flops CE, CF, and CG, in the counter 508 to reset these flip-flops to their reset condition at the end of the reception of each character from the signaling channel 404'. The reset terminal of the flip-flop 423 is coupled to the trigger input of a flip-flop 510 and sets the flip-flop 510 on the trailing edge of the signal from the reset terminal of the flip-flop 423 when this flip-flop is set. When the flip-flop 510 is set, a low potential reset signal is removed from a conductor 444 (FIG. 20) to permit an output flip-flop 451 to be set under the control of the signal supplied by the sense conductor 447. Thus, at the beginning of a readout operation from the matrix 437, the reset or 0" output of the flip-flop 451 is at a more positive potential.

The setting of the flip-flop 510 (FIG. 22) also supplies one enabling input to a gate 512, the other input of which is coupled through an inverter 514 to the output of the amplifier 403". When the first bit signal from the transducer 403 is received, the gate 512 is fully enabled and the more negative potential at its output is applied to the trigger or clock terminal of a first flip-flop CA in the counting circuit 506, which counting circuit also includes three additional flip-flops CB-CD. Thus, the flip-flop CA is now set and the flip-flops CB-CD are reset. This setting of the counter 506 is translated in the network 446 to apply an enabling potential to the gate terminal of the rectifier 446-1. In the reset condition of the counter 508, the network 445 is controlled to apply an enabling potential to the gate electrode of the rectifier 445-1. Thus, the first horizontal read conductor 1H and the first vertical read conductor IV are partially enabled.

The output of the gate 512 (FIG. 22) is also connected to the input of a monostable circuit 452 (FIG. 20 and 32). When the output of the gate 512 is at its normal high potential, a capacitor in the input circuit to the monostable circuit 452 becomes charged, and when the output of the gate 512 drops to a more negative potential, the left-hand transistor in the circuit 452 (FIG. 32) is placed in a nonconductive condition, and the right-hand transistor in this figure is placed in a conductive condition. The conductive condition of this transistor forwards a more negative potential over a conductor 452" to the base of the transistor 453 to place this transistor in a conductive condition so that coincident horizontal and vertical write currents are applied to the first core C1 in the matrix 437. Since this core was set in storing the character E in the matrix 437, the core is now reset and delivers a voltage pulse over the sense winding 447 and the sense amplifier 448 to one input of gate 449 over a conductor 448 (FIG. 20) representing a mark or the presence of a bit. The amplifier 448 delivers a negativegoing signal representing a mark pulse and provides a more positive signal when a signal is not received from the sense winding 447 representing the absence of a reset core or the absence of a bit in the positional code.

The more negative signal applied by the conductor 448' to one input of the gate 449 provides a more positive potential at the output of this gate which is applied to the set input terminal of the flip-flop 451. This more positive potential is also applied to one input of a gate 449' which together with the gate 449 provides a bistable circuit 450. The output of the gate 449' is returned to the other input terminal of the flipflop 451. The other input to the gate 449' is supplied by a conductor 452 which is connected to the collector of the lefthand transistor in the monostable circuit 452 (FIG. 32). Since this transistor is now in a nonconductive state, a more positive potential is applied to the trigger input of the flip-flop 451 and to the upper input to the gate 449. Thus, the gate 449' is now fully enabled and applies a more negative potential to the reset input terminal of the flip-flop 451 and the upper input to the gate 449, thus holding the output of the gate 449 at a more positive potential.

When the monostable circuit 452 times out to terminate conduction through the transistor 453 and thus terminate the read current supplied to the conductors 1V and III, the negative-going voltage on the conductor 452' sets the flip-flop 451 so that a more negative potential is applied by the reset output terminal of this flip-flop to the input of a pair of circuits 454 and 455 which are coupled to the winding 316 controlling the operation of the print hammer 299. As set forth above, the winding 316 is normally energized through a normally conductive transistor Q24 (FIG. 30) to maintain the hammer in a retracted position. However, when a more negative potential is applied to the circuit 455, the transistor 04 is placed in a nonconductive, condition, the energization of the winding 316 is terminated, and the hammer 299 strikes against the adjacent recording element 138 of the platen 127 to produce a record in the area shown as L13 in FIG. 21. The circuit 454 is shown and described in detail in U.S. Pat. No. 3,386,378, and the transistor Q24 corresponds to the transistor 24 in this patent.

The negative-going pulse on the conductor 452' which sets the flip-flop 452 also applies a more negative input to the upper input of the gate 449' so that is output rises to a more positive potential. Since the momentary negative-going pulse on the conductor 448' has now been dissipated, both inputs to the gate 449' are at a more positive potential. The output of the gate 449 also applies a more positive input to the reset input terminal of the flip-flop 451, and the input to the reset input of the flip-flop 451 is now at a more positive potential. Thus, if a bit is not stored in the next interrogated core in the matrix 437, the negative-going pulse applied to the conductor 452' by the monostable circuit 452 will result in resetting of the flip-flop 451. Alternatively, if a pulse is received from the sense winding 447 on interrogation of the next core, the flipflop 451 will merely remain in its set condition even through the bistable circuit 450 will have been operated between its two alternate states by the time the next clock pulse is received on the conductor 452'.

The remaining nine pulses developed by the slots 403' on the clock or timing wheel 401 advance the counter 506 through a cycle of operation, and as the counter 506 is advanced through this cycle of operating, andis the counter 506 is advanced through this cycle of operation, the remaining horizontal read conductors including the conductor 2H are energized in sequence to interrogate the remaining cores C2-C7 in the first column in sequence in the manner described above. This produce. intermittent operation of the print hammer 299 under the control of the winding or print coil 316 in dependence on the bit stored in the first column, in the matrix 437.

As the counter 506 advances through the cycle of operation and returns to its normal state, the translating or decoding network 446, in passing beyond the position at which the uppermost of the horizontal read conductors is enabled, delivers an operating signal over a conductor 446' to the clock terminal of the first flip-flop CE in the counting circuit 508. This advances this counting circuit a single step to remove the enabling potential from the gate electrode of the rectifier 445-1 connected to the first vertical read conductor 1V and to apply an enabling potential to the gate terminal of the rectifier terminating one end of the second column or vertical read conductor 2V. Thus, during the next cycle of operation of the counting circuit 506, the seven cores in the second column are interrogated in sequence using coincident current techniques. In a similar manner, the counting circuits 506 and 508 and the translating networks 446 and 445 interrogate the remaining cores in the matrix 437 to control the application of signals over the sense winding 447 to the amplifier 448 which in turn controls the setting of the flip-flop 451 and the energization of the winding 316 to effect recording of the desired character.

A gate 514 (FIG. 22) is enabled by the flip-flops CF and CG and the output of the amplifier 403' at the conclusion of the scanning of the matrix 437 to reset the flip-flops 510 to a reset state in which a more negative potential is provided at the set output of this flip-flop. This removes the enabling potential from one input to the gate 512 and primes of flipflop 451 to its reset state in which a more positive potential is applied to the circuit 455. This aids in restoring the receiver circuit to a normal condition awaiting the receipt of the next Baudot coded character in the flip-flop 502.

In this manner, each character received from the channel 404 is stored in the flip-flops 502 in Baudot-coded form and cations L13 and L59. Once the operation of the commutator is initiated, the commutator 444 is driven one step or count each time the transducer 403 senses the slot 403', thereby advancing the commutator from count 0 to count I represented by grid block location L1 in FIG. 21 (even through no dot or mark can be printed until count 12 is reached). When the next slot 403' is sensed by the transducer 403, the commutator 444 is advanced from count I to count 2 represented by the grid block location L2. When the transducer 403 senses the next slot 403', 0 the commutator 444 is advanced from count 2 to count 3 represented by grid block location L3. The time between count 0 and count 12 provides more than adequate time for the clutch 203 to be engaged, for the feed screw 193 to reach constant rotational speed, and for storing the signal representative of the symbol in the memory device 437. It is apparent from FIG. 20 that the symbol signal is stored in the 5X7 array or matrix, and hence the symbol is printed on the record medium in a 5X7 grid block arrangement at predetermined locations between location L13 and location L59, inclusive. Printing can commence at location L13 when the commutator 444 starts advancing from count 12 to count l3, As the print coil 316remains deenergized from count 12 up to count 19 the print hammer 299 remains in printing cooperation with the platenelement 138, thereby causing the vertical line portion of the symbol E to be scribed. The print coil 316 is energized as soon as printing has occurred at location L19, so that no printing will occur at location L20. There is no core in the memory device 437 which corresponds to location L20. The commutator 444 continues to be advanced by each successive slot 403' from count 19 to count 22. When count 22 is reached the next successive platen element 138 is in the proper position with respect to the print face 142. The time interval between count I9 and count 22 provides time for the next successive platen element 138 to rotate into proper position with respect to the face 142 of the print hammer 299. In like manner, all the dots or marks in the vertical column with grid block locations L33 through L39 are printed when the print hammer 299 cooperates with the next successive platen element 138, and so on.'Progressive printing of the symbol E is complete when a dot or mark is printed at location L59.

In the embodiment of FIGS. 20 and 22 through 34 and also in the embodiment of FIG. 35, two sensing members, specifically transducers, 402 and 403 are used in conjunction with the clockwheel 401. The arrangement by which the clockwheel 401 and the sensing members 402 and 403 are mounted in the printer 37 is illustrated in detail in FIGS. 25, 26 and 27. Electric motor 199 is secured to a subframe 121 by fasteners 470. The subframe 121' has an upstanding portion 472 which threadably receives a machine screw 473. A mounting assembly 474 has a central bearing 475 received by motor shaft 476. The mounting assembly 474 includes a pair of clamp arms 477 and 478 which mount the sensing members 402 and 403. The clockwheel is secured to the shaft 476. The sensing member 402 is disposed outwardly of and in alignment with the four slots 402', and the sensing member 403 is disposed outwardly of and in alignment with the four slots 402, and the sensing member 403 is disposed outwardly of and in alignment with the 40 slots 403. As best shown in FIG. 27, the sensing member 402 is clamped in position when machine screw 488 is tightened. The gap between the sensing member 402 and the outer surface of the clockwheel 401 can be adjusted by loosening the machine screw 488, making the adjustment, and thereafter tightening the machine screw 488 to hold the sensing member 402 in its adjusted position. The sensing member 403 is adjustably clamped by structure like that shown in FIG. 27. The mounting structure 474 is always centered on the shaft 476. Thus, as the shaft 476 rotates, the sensing members 402 and 403 are always in adjusted relationship with respect to the outer surface of the clockwheel 401. The slots 402' and 403' are made long enough so that in spite of any end play in the shaft 476 the sensing members 402 and 403 are not affected by it. As best shown in FIG. 26, the sensing members 402 and 403 are 180 apart.

In printing of a selected symbol on the record medium R, any dot or mark which is to be printed in the first column, that is, at any one of the grid block locations L13 through L19, is printed by the print face 142 of the print hammer 299 cooperating with one of the platen edges; any dot or mark which is to be printed in the second column, that is at any one of the locations L23 through L29 is printed by the print face 142 with the next successive platen edge 138; and so on. When a symbol signal has been read into the memory device 437, the first slot 402' sensed by the sensing member 402 will start the commutator 444. The remaining slots 402' have no effect on the commutator 444 which is now advanced under the control of slots 403' and sensing member 403. The platen element 138 which is presented in the printing zone when the commutator 444 reaches count 12, in cooperation with the print face 142, will effect printing at each location L13 through L19 where required as dictated by signal stored in the memory device 437: the next platen element 138 on the outer surface on the platen 127 will effect printing at each location L23 through L29; and so on. Thus, once the symbol is ready to be printed, any one or all of five successive platen elements are used.

In order to insure that the printing cycle is always initiated such that the platen element which can print at the first seven vertical locations L13 through L19 is in the proper position with respect to the print face 142, it is desirable to provide for rotation of the sensing members 402 and 403 as a unit with respect to the clockwheel 401. To this end, an arcuate slot 489 is provided for the mounting assembly 474. The machine screw 473 passes through the center of the slot 489. When the screw 473 is tightened, the mounting assembly 474 is clamped to the upstanding portion 472 of the subframe 121'. To adjust the sensing members 402 and 403 with respect to the clockwheel 401, the screw 473 is loosened and the mounting assembly 474 is rotated with respect and about the shaft 476. The screw 473 is tightened when the adjustment has been made, thereby clamping the mounting assembly 474 is its adjusted position. By mounting the mounting assembly 474 directly on the shaft 476, the sensing members 402 and 403 always remain in adjusted positions relative to the clockwheel 401 in radial directions outwardly from the axis of the shaft 476.

In the embodiment of FIG. 35 there is illustrated an arrangement by which signals can be stored in the memory device such as the memory device 437, directly from a keyboard generally indicated at 495. in particular, the arrangement shown in FIG. 35 is used to store a symbol representative signal and to initiate the printing cycle by initiating operation of commutator 444 and by initiating engagement of the clutch 203. The keyboard 495 has a plurality of keys 496. When a selected key 496 is depressed, it completes a circuit via respective switch 497 through its respective winding 438 to sense amplifier 498. Each winding 438 is roped through the memory device in an arrangement representative of the selected symbol. The sense amplifier 448 thereupon sets the control flip-flop 423. When a gate 499 is enabled by the next clock element 402', the flip-flop 423 is reset and operates a one-shot 440a corresponding to the one-shot 440, thereby energizing clutch coil 229 to effect engagement of the clutch 203. Resetting of the flip-flop 423 also initiates operation of the commutator 444 (FIG. via conductor 443. Depression of a carriage return key 496' causes closure of switch 497', thereby operating one-shot 4400 to energize the coil 229 and causing inverting amplifier 460a, which corresponds to inverting amplifier 460, to turn on silicon-controlled rectifier 461, thereby energizing carriage return coil 158.

Other embodiments and modifications of this invention will suggest themselves to those skilled in the art, andall such of these as come within the spirit of this invention are included within its scope as best defined by the appended claims.

I claim:

1. For a printing system: a transmitter having symbol selecting means for effecting generation of electrical signals and having signal storage means, each electrical signal having a multiplicity of selectively spaced sequential pulse units representative of the selected symbol, means responsive to said electrical signals for printing the selected symbols on a record medium, said selected symbol being progressively printed during a printing cycle, said printing means including recording means having a continuously moving recording member, means for continuously driving said recording means, a carriage mounted for travel with respect to said recording means, said carriage having means responsive to readout of symbol pulse units from said storage means and cooperable with said recording member for progressively printing the selected symbol on the record medium during the progressive printing cycle while said carriage is travelling, start-stop means for starting and stopping said carriage once for each printing cycle, cam means attached to said recording means for sensing the position of said recording member, and switch means responsive to said cam means for synchronizing the initiation of each printing cycle with the position of said recording member.

2. For a printing system: means responsive to electrical signals for printing symbols on a record medium, each electrical signal having a multiplicity of selectively spaced sequential symbol pulse units representative of the selected symbol, said selected symbol being progressively printed during a printing cycle, said printing means including recording means having a continuously moving recording member, means for continuously driving said recording means, a carriage mounted for travel with respect to said recording means, said carriage having means responsive to said symbol pulse units and cooperable with said recording member for progressively printing the selected symbol on the record medium during the progressive printing cycle while said carriage is traveling, start-stop means for starting and stopping said carriage once for each printing cycle, cam means attached to said recording means for sensing the position of said recording member, and switch means responsive to said cam means for synchronizing the initiation of each printing cycle with the position of said recording member.

3. For printing system: a transmitter having symbol-selecting means for effecting generation of electrical signals and having commutator means, each electrical signal having a multiplicity of selectively spaced sequential pulse units representative of the selected symbols, a printer responsive to said electrical signals for printing in the selected symbols on a record medium, each symbol being progressively printed during a printing cycle, said printer having at least one continuously moving platen element, means for continuously driving said platen element, printing means cooperable with said platen element, a carriage mounting said printing means for relative movement with respect to said platen element, startstop means for causing said carriage to start, travel and stop once for each symbol recordation, cam means attached to said printer for sensing the position of said platen element, commutator means, switching means responsive to said cam means when a selected symbol is to be printed for initiating operation of said commutator means, and means responsive to said commutator means for operating said printing means to progressively print the selected symbol on the record medium as said carriage travels.

4. For a printing system: a printer for progressively printing symbols in successive symbol rectangular spaces on a record medium, said printer having at least one continuously moving first recording member, means for continuously driving said first recording member, a second recording member cooperable with said first recording member, a carriage mounting said second recording member for relative movement with respect to said first recording member, start-stop means for causing said carriage to start, travel and stop once for each symbol recordation, cam means for sensing the position of said first recording member, commutator means, switch means, actuated by said cam means when a selected symbol is to be printed for initiating operation of said commutator means, and means responsive to said commutator means for operating said second recording member to progressively print selected symbol on the record medium as said carriage travels.

5. The invention as defined in claim 4, including a transmitter having a symbol-selecting means coupled to said commutator means.

6. The invention as defined in claim 4, including symbolselecting means coupled to said commutator means, said symbol-selecting means including a keyboard transmitter.

7. The invention as defined in claim 4, including symbolselecting means coupled to said commutator means, said symbol-selecting means including a reader.

8. The invention defined in claim 4, including means associated with said commutator means for storing a signal composed of a multiplicity of intra-signal pulse units to which said printing means is responsive.

9. For a printing system: means responsive to electrical signals for printing symbols on a record medium, each electrical signal having a multiplicity of selectively spaced sequential symbol pulse units representative of the selected symbol, each symbol being progressively printed during a printing cycle, a signal storage means, said'printing means including recording means having a continuously moving recording member, means for continuously driving said recording means, a carriage mounted for travel with respect to said recording means, said carriage having means responsive to readout of symbol pulse units from said signal storage means and cooperable with said recording member for progressively printing the selected symbol on the record medium during the progressive printing cycle while said carriage is traveling, sensing means connected to said recording means for sensing the position of said recording member, and responsive means responsive to said sensing means for synchronizing the initiation of each printing cycle with the position of said recording member.

10. For a printing system: recording means having at least one continuously moving first line-shaped recording member, means for continuously driving said first recording member, a carriage mounted for travel with respect to said first recording member, said carriage having a second recording member having a line-shaped face cooperable with said first recording member for progressively printing the selected symbol on the record medium during a progressive printing cycle while said carriage is traveling, start-stop means for starting and stopping travel of said carriage once for each printing cycle, sensing means associated with said first recording member for sensing the position of said first recording member, and means responsive to said sensing means for synchronizing the initiation of each printing cycle with the position of said first recording member.

11. For a printing system: a printer having first printing means, a traveling carriage movable relative to said first printing means away from and toward a start-of-line position, said carriage having a guide bearing and second printing means cooperable with said first printing means, a rotatable driven feed screw extending through and guiding said guide bearing, coupling means for selectively coupling and uncoupling said carriage and said feed screw, said coupling means being effective in its coupled position to provide a drive connection between carriage and said feed screw to advance said carriage away from the start-of-line position, said bearing being slidable on said feed screw when said coupling means is uncoupled to enable return of said carriage to the start-of-line position and a member pivotal between two positions, said pivotal member being effective in one position to enable uncoupling of said coupling means and effective in the other position to drive said coupling means into meshing engagement with said feed screw, said feed screw and said pivotal member being the sole means by WhlCh said carriage IS guided relative to said first printing member.

12. A recording unit as defined in claim 11, wherein said bearing has a slot, and said coupling means includes a movable coupling member engageable snugly in said slot and cooperable with said feed screw so that driving force from said feed screw is imparted to said bearing through said coupling member.

13. The invention as defined in claim 11, including roller means mounted by said carriage and in rolling contact with said pivotal member.

14. A printer as defined in claim 11, wherein said coupling means includes a member engageable with said feed screw and said bearing.

15. For a printing system: a printer having a carriage movable relative to said platen away from and toward a start-of-line position, said carriage having a guide bearing, a rotatable feed screw for driving said carriage received in guiding relationship by said feed screw, a pivotal guiding and actuating member, a coupling member mounted by said carriage and movable between a first position in engagement with said bearing and said feed screw so that drive force is imparted to said carriage at said bearing and a second position out of engagement with said feed screw so that said carriage can return to the start-ofline position, and a roller mounted by said carriage in rolling contact with said guiding and actuating member, said guiding and actuating member being operable while said coupling member is in its first position to exert force against said coupling member to urge said roller against said guiding and actuating member, said feed screw and said actuating and guiding member being the sole guides for said carriage. 

1. For a printing system: a transmitter having symbol selecting means for effecting generation of electrical signals and having signal storage means, each electrical signal having a multiplicity of selectively spaced sequential pulse units representative of the selected symbol, means responsive to said electrical signals for printing the selected symbols on a record medium, said selected symbol being progressively printed during a printing cycle, said printing means including recording means having a continuously moving recording member, means for continuously driving said recording means, a carriage mounted for travel with respect to said recording means, said carriage having means resPonsive to readout of symbol pulse units from said storage means and cooperable with said recording member for progressively printing the selected symbol on the record medium during the progressive printing cycle while said carriage is travelling, start-stop means for starting and stopping said carriage once for each printing cycle, cam means attached to said recording means for sensing the position of said recording member, and switch means responsive to said cam means for synchronizing the initiation of each printing cycle with the position of said recording member.
 2. For a printing system: means responsive to electrical signals for printing symbols on a record medium, each electrical signal having a multiplicity of selectively spaced sequential symbol pulse units representative of the selected symbol, said selected symbol being progressively printed during a printing cycle, said printing means including recording means having a continuously moving recording member, means for continuously driving said recording means, a carriage mounted for travel with respect to said recording means, said carriage having means responsive to said symbol pulse units and cooperable with said recording member for progressively printing the selected symbol on the record medium during the progressive printing cycle while said carriage is traveling, start-stop means for starting and stopping said carriage once for each printing cycle, cam means attached to said recording means for sensing the position of said recording member, and switch means responsive to said cam means for synchronizing the initiation of each printing cycle with the position of said recording member.
 3. For printing system: a transmitter having symbol-selecting means for effecting generation of electrical signals and having commutator means, each electrical signal having a multiplicity of selectively spaced sequential pulse units representative of the selected symbols, a printer responsive to said electrical signals for printing in the selected symbols on a record medium, each symbol being progressively printed during a printing cycle, said printer having at least one continuously moving platen element, means for continuously driving said platen element, printing means cooperable with said platen element, a carriage mounting said printing means for relative movement with respect to said platen element, start-stop means for causing said carriage to start, travel and stop once for each symbol recordation, cam means attached to said printer for sensing the position of said platen element, commutator means, switching means responsive to said cam means when a selected symbol is to be printed for initiating operation of said commutator means, and means responsive to said commutator means for operating said printing means to progressively print the selected symbol on the record medium as said carriage travels.
 4. For a printing system: a printer for progressively printing symbols in successive symbol rectangular spaces on a record medium, said printer having at least one continuously moving first recording member, means for continuously driving said first recording member, a second recording member cooperable with said first recording member, a carriage mounting said second recording member for relative movement with respect to said first recording member, start-stop means for causing said carriage to start, travel and stop once for each symbol recordation, cam means for sensing the position of said first recording member, commutator means, switch means, actuated by said cam means when a selected symbol is to be printed for initiating operation of said commutator means, and means responsive to said commutator means for operating said second recording member to progressively print selected symbol on the record medium as said carriage travels.
 5. The invention as defined in claim 4, including a transmitter having a symbol-selecting means coupled to said commutator means.
 6. The invention as defined in claim 4, includinG symbol-selecting means coupled to said commutator means, said symbol-selecting means including a keyboard transmitter.
 7. The invention as defined in claim 4, including symbol-selecting means coupled to said commutator means, said symbol-selecting means including a reader.
 8. The invention defined in claim 4, including means associated with said commutator means for storing a signal composed of a multiplicity of intra-signal pulse units to which said printing means is responsive.
 9. For a printing system: means responsive to electrical signals for printing symbols on a record medium, each electrical signal having a multiplicity of selectively spaced sequential symbol pulse units representative of the selected symbol, each symbol being progressively printed during a printing cycle, a signal storage means, said printing means including recording means having a continuously moving recording member, means for continuously driving said recording means, a carriage mounted for travel with respect to said recording means, said carriage having means responsive to readout of symbol pulse units from said signal storage means and cooperable with said recording member for progressively printing the selected symbol on the record medium during the progressive printing cycle while said carriage is traveling, sensing means connected to said recording means for sensing the position of said recording member, and responsive means responsive to said sensing means for synchronizing the initiation of each printing cycle with the position of said recording member.
 10. For a printing system: recording means having at least one continuously moving first line-shaped recording member, means for continuously driving said first recording member, a carriage mounted for travel with respect to said first recording member, said carriage having a second recording member having a line-shaped face cooperable with said first recording member for progressively printing the selected symbol on the record medium during a progressive printing cycle while said carriage is traveling, start-stop means for starting and stopping travel of said carriage once for each printing cycle, sensing means associated with said first recording member for sensing the position of said first recording member, and means responsive to said sensing means for synchronizing the initiation of each printing cycle with the position of said first recording member.
 11. For a printing system: a printer having first printing means, a traveling carriage movable relative to said first printing means away from and toward a start-of-line position, said carriage having a guide bearing and second printing means cooperable with said first printing means, a rotatable driven feed screw extending through and guiding said guide bearing, coupling means for selectively coupling and uncoupling said carriage and said feed screw, said coupling means being effective in its coupled position to provide a drive connection between carriage and said feed screw to advance said carriage away from the start-of-line position, said bearing being slidable on said feed screw when said coupling means is uncoupled to enable return of said carriage to the start-of-line position and a member pivotal between two positions, said pivotal member being effective in one position to enable uncoupling of said coupling means and effective in the other position to drive said coupling means into meshing engagement with said feed screw, said feed screw and said pivotal member being the sole means by which said carriage is guided relative to said first printing member.
 12. A recording unit as defined in claim 11, wherein said bearing has a slot, and said coupling means includes a movable coupling member engageable snugly in said slot and cooperable with said feed screw so that driving force from said feed screw is imparted to said bearing through said coupling member.
 13. The invention as defined in claim 11, including roller means mounted by said carriage and in rolling contact with said pivotal member.
 14. A printer as defined in claim 11, wherein said coupling means includes a member engageable with said feed screw and said bearing.
 15. For a printing system: a printer having a carriage movable relative to said platen away from and toward a start-of-line position, said carriage having a guide bearing, a rotatable feed screw for driving said carriage received in guiding relationship by said feed screw, a pivotal guiding and actuating member, a coupling member mounted by said carriage and movable between a first position in engagement with said bearing and said feed screw so that drive force is imparted to said carriage at said bearing and a second position out of engagement with said feed screw so that said carriage can return to the start-of-line position, and a roller mounted by said carriage in rolling contact with said guiding and actuating member, said guiding and actuating member being operable while said coupling member is in its first position to exert force against said coupling member to urge said roller against said guiding and actuating member, said feed screw and said actuating and guiding member being the sole guides for said carriage. 